Once fleeing troops have been moved, victorious units will pursue. To find out how far they pursue, starting with the unit with the highest Unit Strength, roll 2D6 or 3D6 in exactly the same way as for fleeing troops. This is their Pursuit roll. If a victorious unit scores equal to or greater than the Flee roll scored by the unit it is pursuing then the fleeing unit is completely destroyed - all the troops are cut down as they run or they are scattered beyond hope of regrouping. Pursuers are moved the full distance indicated straight towards the fleeing troops, and through their position if their pursuit move is especially long. If the pursuers do not roll a sufficiently high score to catch the fleeing unit then no furher casualties are caused and the pursuers are simply moved the distance indicated towards their fleeing enemies. Pursuers always move their full pursuit distance unless their pursuit takes them into concacc with fresh enemy. During a pursuit move, pursuers ignore any penalties for obstacles and terrain (apart from impassable terrain) - their victory has given them the extra impems to chase their fleeing enemies.
Note that units do not continue to pursue in subsequent turns; pursuit is a single bonus move which is made when a beaten enemy flees. One unit can only pursue one fleeing enemy unit, even if it broke several units in close combat.